The invention relates to a method for operating a fuel cell apparatus or device, in which method electrical energy is made available with a fuel cell and at least partially stored. In addition, the invention relates to a fuel cell apparatus or device having a fuel cell and an accumulator for electrical energy, which is connected to the fuel cell in an energy-transmitting fashion. Furthermore, the invention relates to a motor vehicle having a drive system and a fuel cell apparatus or device which is connected to the drive system in a drive energy-transmitting fashion.
Methods for operating fuel cell devices and fuel cell devices and motor vehicles with fuel cell devices are generally known. For example, documents DE 102012018710 A1 and DE 1 0201 31 01 826 A1 disclose fuel cell apparatuses or devices with accumulators.
In order to be able to keep the fuel cell in an optimum operating state, the electric accumulator is used and, for example, filled with electrical energy if a consumer of the fuel cell energy requires only a small amount of energy. The fuel cell can, therefore, be operated in an optimum operating state in which it generates more energy than the consumer requires. In the optimum operating state, the fuel cell can, for example, be operated with a high efficiency level. Furthermore, the accumulator can output energy to the consumer if the latter requires more energy than the fuel cell can make available, in particular in its optimum operating state.
However, if ambient temperatures which are below an optimum ambient temperature for the operation of the fuel cell prevail when the fuel cell is put into operation, the fuel cell has to be heated up in order to reach an optimum operating temperature as quickly as possible. However, if the consumer requests only a small amount of electrical energy from the fuel cell, and the accumulator cannot take up any energy, the fuel cell must be heated in order to be able to raise its operating temperature as quickly as possible to an optimum range. However, heating the fuel cell, for example with a heating device which can be operated electrically, requires energy which is then no longer available for the consumer.